A5050428979- Receptor Mechanisms and Signaling
- Neuroscience and Neuropharmacology Research
- Neurotransmitter Receptor Influence on Behavior
- Ion channel regulation and function
- Forensic Toxicology and Drug Analysis
- Adenosine and Purinergic Signaling
- Amino Acid Enzymes and Metabolism
- Nicotinic Acetylcholine Receptors Study
- Cellular transport and secretion
- Cannabis and Cannabinoid Research
- Lipid Membrane Structure and Behavior
- Psychedelics and Drug Studies
- Cell Adhesion Molecules Research
- Neuropeptides and Animal Physiology
- DNA and Nucleic Acid Chemistry
- Cardiac electrophysiology and arrhythmias
- Force Microscopy Techniques and Applications
- Pharmacological Receptor Mechanisms and Effects
- Cellular Mechanics and Interactions
- Peroxisome Proliferator-Activated Receptors
- Drug Transport and Resistance Mechanisms
- Helminth infection and control
- Coccidia and coccidiosis research
- Genetic Syndromes and Imprinting
- Bipolar Disorder and Treatment
Medical University of Vienna
2015-2024
Institute of Pharmacology
2000-2015
Max Planck Society
2005-2006
Max Planck Institute of Biochemistry
2005
University of Chicago
2001-2005
University of Vienna
2000-2003
Howard Hughes Medical Institute
2003
St. Jude Children's Research Hospital
2003
Universität Ulm
2002
Recent biochemical studies indicate that the serotonin transporter can form oligomers. We investigated whether human (hSERT) be visualized as an oligomer in plasma membrane of intact cells. For this purpose, we generated fusion proteins hSERT and spectral variants green fluorescent protein (cyan yellow proteins, CFP YFP, respectively). When expressed embryonic kidney 293 cells, resulting (CFP-hSERT YFP-hSERT) were efficiently inserted into functionally indistinguishable from wild-type hSERT....
The serotonin transporter (SERT) terminates neurotransmission by removing from the synaptic cleft. In addition, it is site of action antidepressants (which block transporter) and amphetamines induce substrate efflux). We explored functional importance N terminus in mediating focusing initially on highly conserved threonine residue at position 81, a candidate for phosphorylation protein kinase C. Molecular dynamics simulations wild type SERT, compared with its mutations SERT(T81A) SERT(T81D),...
Psychostimulants such as amphetamine and cocaine are illicitly used drugs that act on neurotransmitter transporters for dopamine, serotonin or norepinephrine. These can by themselves already cause severe neurotoxicity. However, an additional health threat arises from adulterant substances which added to the illicit compound without declaration. One of most frequently adulterants in street sold is anthelmintic drug levamisole. We tested effects levamisole heterologously expressed HEK293...
Abstract Organic cation transporters (OCTs) facilitate the translocation of catecholamines, drugs and xenobiotics across plasma membrane in various tissues throughout human body. OCT3 plays a key role low-affinity, high-capacity uptake monoamines most including heart, brain liver. Its deregulation diseases. Despite its importance, structural basis function inhibition has remained enigmatic. Here we describe cryo-EM structure at 3.2 Å resolution. Structures bound to two inhibitors,...
Amphetamine congeners [e.g., 3,4-methylenedioxymetamphetamine (MDMA), or "ecstasy"] are substrates for monoamine transporters (i.e., the serotonin, norepinephrine, and dopamine); however, their in vivo-action relies on ability to promote efflux. The mechanistic basis this counter transport remains enigmatic. We tested hypothesis that outward is contingent oligomeric nature of neurotransmitter by creating a concatemer serotonin transporter amphetamine-resistant GABA transporter. In cells...
The transporters for serotonin (SERT), dopamine, and noradrenaline have a conserved hydrophobic core but divergent N C termini. terminus harbors the binding site coat protein complex II (COPII) cargo-binding SEC24. Here we explored which SEC24 isoform was required export of SERT from endoplasmic reticulum (ER). Three lines evidence argue that can only exit ER by recruiting SEC24C: (i) Mass spectrometry showed peptide corresponding to recruited SEC24C-containing COPII complexes mouse brain...
Nerve functions require phosphatidylinositol-4,5-bisphosphate (PIP 2 ) that binds to ion channels, thereby controlling their gating. Channel properties are also attributed serotonin transporters (SERTs); however, SERT regulation by PIP has not been reported. SERTs control neurotransmission removing from the extracellular space. An increase in results transporter-mediated efflux triggered amphetamine-like psychostimulants. Herein, we altered abundance of activating phospholipase-C (PLC),...
Abstract The human serotonin transporter (hSERT) mediates uptake of from the synaptic cleft and thereby terminates serotonergic signalling. We have previously found by single-molecule microscopy that SERT forms stable higher-order oligomers differing stoichiometry at plasma membrane living cells. Here, we report oligomer assembly endoplasmic reticulum (ER) follows a dynamic equilibration process, characterized rapid exchange subunits between different oligomers, concentration dependence...
Signaling by D<sub>2</sub>-dopamine receptors in neurons likely proceeds the presence of Ca<sup>2+</sup> oscillations. We describe here biochemical basis for a cross-talk between intracellular and D<sub>2</sub> receptor. By activation calmodulin (CaM), directly inhibits receptor; this conclusion is based on following observations: (i) The receptor contains CaM-binding motif NH<sub>2</sub>-terminal end third loop, domain involved activating G<sub>i/o</sub>. A peptide fragment encompassing...
Na+/Cl–-dependent neurotransmitter transporters form constitutive oligomers. The topological arrangement is not known, but a leucine heptad repeat in transmembrane domain (TM) 2 and glycophorin-like motif TM6 have been proposed to stabilize the oligomer. To determine topology, we generated versions of human serotonin transporter (hSERT) that carried cyan or yellow fluorescent proteins at their amino and/or carboxyl terminus. Appropriate pairs were coexpressed measure fluorescence resonance...
PINCH1 is composed of 5 LIM domains, binds integrin-linked kinase (ILK) and locates to integrin-mediated adhesion sites. In order investigate function we generated mice embryonic stem (ES) cell-derived embryoid bodies (EBs) lacking the gene. Similar β1 integrin or Ilk, loss arrested development at peri-implantation stage. contrast Ilk mutants, however, disruption gene produced implantation chambers with visible cell clumps even day 9.5. define phenotype leading lethality made PINCH1-null EBs...
Amphetamine congeners [e.g., 3,4-methylenedioxymetamphetamine (MDMA), or "ecstasy"] are substrates for monoamine transporters (i.e., the serotonin, norepinephrine, and dopamine); however, their in vivo-action relies on ability to promote efflux. The mechanistic basis this counter transport remains enigmatic. We tested hypothesis that outward is contingent oligomeric nature of neurotransmitter by creating a concatemer serotonin transporter amphetamine-resistant GABA transporter. In cells...
The high-resolution crystal structure of the leucine transporter (LeuT) is frequently used as a template for homology models dopamine (DAT). Although similar in structure, DAT differs considerably from LeuT number ways: (i) when compared to LeuT, has very long intracellular amino and carboxyl termini; (ii) share rather low overall sequence identity (22%) (iii) extracellular loop 2 (EL2) substantially longer than that LeuT. Extracellular zinc binds restricts transporter's movement through...
The human serotonin transporter (hSERT) is responsible for the termination of synaptic serotonergic signaling. Although there solid evidence that SERT forms oligomeric complexes, exact stoichiometry complexes and fractions different coexisting states still remain enigmatic. Here we used single molecule fluorescence microscopy to obtain oligomerization state via brightness analysis diffraction-limited fluorescent spots. Heterologously expressed was labeled either with inhibitor JHC 1-64 or...
Uptake of neurotransmitters by sodium-coupled monoamine transporters the NSS family is required for termination synaptic transmission. Transport tightly regulated protein-protein interactions involving small cytoplasmic segments at amino- and carboxy-terminal ends transporter. Although structures homologues provide information about transmembrane regions these transporters, structural arrangement terminal domains remains largely unknown. Here, we combined molecular modeling, biochemical,...
Addiction to psychostimulants (ie, amphetamines and cocaine) imposes a major socioeconomic burden. Prevention treatment represent unmet medical needs, which may be addressed, if the mechanisms underlying psychostimulant action are understood. Cocaine acts as blocker at transporters for dopamine (DAT), serotonin (SERT), norepinephrine (NET), but substrates that do not only block uptake of monoamines also induce substrate efflux by promoting reverse transport. Reverse transport has been focus...
Amphetamine abuse is a major public health concern for which there currently no effective treatment. To develop treatments, the mechanisms by amphetamine produces its abuse-related effects need to be fully understood. It well known that exerts actions targeting high-affinity transporters monoamines, in particular cocaine-sensitive dopamine transporter. Organic cation transporter 3 (OCT3) has recently been found play an important role regulating monoamine signaling. However, whether OCT3...
Like all members of the Na(+)/Cl(-)-dependent neurotransmitter transporter family, rat gamma-aminobutyric acid transporter-1 (GAT1) is sorted and targeted to specialized domains cell surface. Here we identify two discontinuous signals in carboxyl terminus GAT1 that cooperate drive surface expression. This conclusion based on following observations. Upon deletion last 37 amino acids, resulting GAT1-Delta37 remained trapped endoplasmic reticulum. The presence 10 additional residues...
The serotonin transporter (SERT) maintains serotonergic neurotransmission via rapid reuptake of from the synaptic cleft. SERT relies exclusively on coat protein complex II component SEC24C for endoplasmic reticulum (ER) export. closely related transporters noradrenaline and dopamine depend SEC24D. Here, we show that discrimination between SEC24D is specified by residue at position +2 downstream ER export motif ((607)RI(608) in SERT). Substituting Lys(610) with tyrosine, corresponding found...
Abstract Increasing extracellular levels of serotonin (5-HT) in the brain ameliorates symptoms depression and anxiety-related disorders, e.g., social phobias post-traumatic stress disorder. Recent evidence from preclinical clinical studies established therapeutic potential drugs inducing release 5-HT via 5-HT-transporter. Nevertheless, current releasing compounds under investigation carry risk for abuse deleterious side effects. Here, we demonstrate that S -enantiomers certain...